Postal tokens (6)
I believe the answer is:
stamps
'postal tokens' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for stamps that I've seen before include "Brings foot heavily to the ground, as in anger" , "Brings foot down heavily onto the ground" , "Gummed receipts of postal fees" , "Philatelist's interest" , "Brings one's foot down heavily on the envelope" .)